I encounter exact same problem on ThinkPad T60p, and the xgamma workaround resolved the problem for me. Detail information of my system: VGA Card: 01:00.0 VGA compatible controller: ATI Technologies Inc M56GL [Mobility FireGL V5200] Window Manager: Gnome metacity (no compiz installed) Kernel: Linux xxxx 2.6.32-trunk-686 #1 SMP Sun Jan 10 06:32:16 UTC 2010 i686 GNU/Linux Gnome ScreenSaver is installed.